Abstract

An atomic layer deposition reactor has been constructed with quantitative, precision dose control for studying precursor adsorption characteristics and to relate dose quantity and exposure dynamics to fluid flow in both the viscous and molecular flow regimes. A fixed volume of gas, held at a controlled temperature and measured pressure, is dosed into the reaction chamber by computer-controlled pneumatic valves. Dual in situ quartz crystal microbalances provide parallel mass measurement onto two differently coated substrates, which allows adsorption coverage and relative sticking coefficients to be determined. Gas composition in the reaction chamber was analyzed in situ by a quadrupole mass spectrometer. Absolute reactant exposure is unambiguously calculated from the impingement flux, and is related to dose, surface area, and growth rates. A range of control over the dose amount is demonstrated and consequences for film growth control are demonstrated and proposed.

Received 12 August 2012Accepted 11 December 2012Published online 09 January 2013

Acknowledgments:

The authors would like to acknowledge helpful discussions with Orlando Cabarcos and Lloyd Bumm, and partial financial support from the Penn State MRSEC under National Science Foundation (NSF) Grant No. DMR-0820404.